Manhole.



O. T. DOUGHERTY.

MANHOLE.

APPUCATION FILED DCI 31,1914. RENEWED SEPT. 17. 1915.

1,177,850. I Patented Apr. 4, 1916.

\\\ lNl' THE COLUMBIA FLANOGRAPH co.. WASHINGTDN. D c.

1 1m) STATES PATENT oFF- OWEN THOMAS DOUGHERTY, OF ST. PAUL, MINNESOTA.

MANHOLE.-

Specification of Letters Patent.

Application filed October 31, 1914, Serial No. 869,561. Renewed September 17, 1915. Serial No. 51,286.

To all whom it may concern:

Be it known that I, OWEN T. DOUGHERTY. a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements in Manholes, of which the following is a specification.

This invention relates to manholes, and belongs to that class of devices commonly employed to afford access to sewer mains for repairs and cleaning.

This invention includes both the housing usually placed at the top of the brick entrance well to a sewer, and alsothe cover for the housing, and the object of this invention is the production of such a housing and cover having mutually engaging portions of special formation whereby the cover is caused to move spirally into and out of the housing, and by means of which it is believed the cover may be more easily loosened and removed when clogged or frozen in, than is the case with similar devices in general use.

The special construction and arrangement of the parts of this invention are set out in the accompanying drawings, of which Figure 1 represents a vertical cross-section on the broken line g of Fig. 2. Fig. .2- is a top plan view. Fig. 3 is an explanato-r Y sectional view, showing the lugs of the housing out upon the curving line 50-00 of Fig. 2, and the curved surface developed upon a plane to illustrate the forms of the lugs and spaces.

Throughout the description and drawings, the same letter is used to refer to the same part.

The housing A in the drawings is provided with an internal series of inwardly projecting lugs a, spaced apart, and, usually, all but two of the lugs are located somewhat below the upper surface or rim of the housing.

The cover B has a number of downwardly projecting lugs C, and it will be noted that the sides E and e of the lugs a, and the sides 1* and f of the lugs C are inclined, and at different angles. The spaces between the lugs on both the cover and the housing have sides correspondingly inclined. As illustrated, the sides'of the spaces between the lugs a converge downwardly, while the sides of the spaces between the lugs C diverge downwardly.

Two of the lugs, D and (Z, of the housing,

ordinarily situated at opposite points, extend to the upper surface or rim of the housing. The sides of the lugs I) and (Z are. therefore, longer than the sides of the re .maining lugs a of the housing, but they have Patented Apr. a, rare.

this invention, let it be assumed that the 7 cover has been removed and is to be replaced. It is believed to be clear that the cover must be so arranged when about to be replaced that the recesses and 9 will take in'the extended lugs D and (Z. The cover being so positioned, as the cover descends the lugs 'C first come into contact with the sides E of the lugs a, which sides have the greater inclination of the two sides of each lug a. Consequently, the cover in proceeding downwardly takes a spiral path until the side 7 that is the shorter side of lesser inclination of the two inclined sides of the lug C, meets theside e of the lug a having the same inclination and extent. The parts are so proportioned that the cover now rests flush with the upper surface or rim of the housing in the customary manner. In other words, the cover by its weight has slipped down the inclined sides E of the lugs a until its weight presses the side f of each lug C against each side 6 of the lugs a, and it is found in practice that the engagement thus described is sufficient to prevent the cover from rattling as vehicles are driven over it. It is usual to make the recesses G and g a little larger than the tops of the extended lugs D and (Z, andby inserting a wedge tool H in either recess, the cover may be caused to turn, even if clogged by dirt, or frozen. It is not found necessary to hammer the cover loose as is so often done, with the result that the covers spaces and constructed to engage the lugs of the housing whereby the direct vertical displacement of the cover is prevented.

2. In a manhole, the combination with a housing having inwardly projecting spaced lags located. below the upper surface of the housing, the sides of the said lugs being .inclined at different angles whereby spaces are left between the lugs having sides of different inclination, of a cover having downwardly projecting spaced lugs corresponding in form and position to the said spaces and constructed to engage the lugs of the housing whereby direct vertical displacement of the cover is prevented and the upper surface of the cover is flush with the upper surface of the said housing.

3. In a manhole, thecombination with a housing having a lug extending to its upper surface and lugs located below the said surface, the said lugs being spaced apart and having inclined sides, of a-cover having downwardly projecting spaced lugs constructed with inclined sides whereby the spaces between the said lugs of the cover will:

receive the lugs of the housing, and the edge of the cover having a recess constructed to receive the said lug of the housing which extends to the upper'surface thereof.

4:. In a manhole, the combination with a housing having lugs projecting inwardly to- Ward a common vertical center, the said lugs aving sides of different angles of inclination forming downwardly narrowing spaces between the lugs, of a cover having down wardly projecting inclined lugs the angles'35 of inclination being substantiallythesaine as the angles of the said lugs of the housing whereby as the cover is placed upon the said housing the inclined lugs of the cover engaging the inclined lugs ofthe housingywill 40 OWEN THOMAS DOUGHE RTY. Witnesses THOMAS .VVA'ITS, B. E. Cr-rosn.

Ge ies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents: Washington, D. C. 

